1. Field of the Invention
This invention relates to new block copolymers having excellent vibration-damping properties and composition cotaining the same.
2. Description of the Prior Art
In recent years, according to the development of transporation facilities, noises and vibrations have been a significant social problem. In the precision machinery and electronics industries, the adverse effects of vibrations have been a serious problem. Consequently, vibration absorption and vibration-damping properties have been increasingly demanded.
As for vibration absorption and vibration-damping materials, metal springs, air springs, cork, felt, rubber vibration insulators and the like have been utilized. Among those, rubber vibration insulators have been widely adopted due to the form selectivity, low vibration transmisibility in high-frequency range, low cost etc. Hitherto diene rubbers such as neoprene rubbers, styrene-butadiene rubbers and the like have been well known as a vibration insulating rubber (Applied Acoustics vol. 11, pp 77-97 (1978)), but they are unsatisfactory both in vibration absorption and damping, and butyl rubbers have comparatively satisfactory properties in vibration absorption and damping, but are inferior in physical strength. Therefore, neither of them has been satisfied the requirements. All of these rubbers need the process of mixing various additives, vulcanizers and so on, vulcanizing by heat treatment after molding to represent strengths substantially, which requires a great deal of time and labor.